| School | HMC Division | Membership | Location | Age Range |
| King William’s College | North West (UK) | British Isles | Castletown, Isle of Man | 4 - 18 |
| Sir William Perkins’s School | London (UK) | British Isles | Chertsey, Surrey, United Kingdom | 11 - 18 |
| The British School of Milan | International | International | Milan, Italy | 3 - 18 |
King William’s College
Age range
4 - 18
Location
Castletown, IM9 1TP, Isle of Man
Head’s name
Damian Henderson
Sir William Perkins’s School
Age range
11 - 18
Location
Guildford Road, Chertsey, Surrey, KT16 9BN, United Kingdom
Head’s name
Debbie Picton
The British School of Milan
Age range
3 - 18
Location
Via Carlo Alberto Pisani Dossi, 16, 20134 Milano MI, Italy
Head’s name
Simon Lockyer